The basic goal of this project is an analysis of the neural systems and mechanisms underlying auditory learning and discrimination. Patterns of activity of single neurons in auditory and association areas of the cerebral cortex are being studied in anesthetized and unanesthetized preparations. In new research, simultaneous recording of single neuron activity and behavioral responses will be done during acoustic discrimination behavior and analyzed in the context of signal detection theory. The initial focus in this project will be the cochlear nucleus. BIBLIOGRAPHIC REFERENCES: Berger, T.W. neuronal plasticity in the limbic system during classical conditioning. Doctoral Dissertation, Harvard University, 1976. Cegavske, C.F., Thompson, R.F., Patterson, M.M., and Gormezano, I. Mechanisms of efferent neuronal control of the reflex nicititating membrane response in the rabbit. J. comp. physiol. Psychol., 1976, 90, 411-423.